Apparatus for drawing of synthetic fibres



p 19% J. PFENNINGSBERG E L 5 APPARATUS FOR DRAWING 0F SYNTHETIC FIBRESFiled Jan. 23', 1953 4 Sheets-Sheet 1 Sept. 30, 1958 Filed Jan. 25, 1953J. PFEb lNlNGSBEl RG ETAL. 2,853,738

APPARATUS FOR DRAWING 0 SYNTHETIC, FIBRES 4 Sheets-Sheet 2 Sept. 30,1958 J. PFENNINGSBERG ETAL 2,353,738

APPARATUS FOR DRAWING OF SYNTHETIC FIBRES Filed Jan. 25, 1953 4Sheets-Sheet 3 Inventor's 7. Pfennagf i/cjz 61 Sept. 30, 1958 J.PFENNINGSBERG ETAL 5 APPARATUS FOR DRAWING OF SYNTHETIC FIBRES FiledJan. 23, 1953 4 Sheets-Sheet 4 Invemors c7. PfenILLn s berg UniteAPPARATUS FOR DRAWING F SYNTHETIC FIBRES Application January 23, 1953,Serial No. 332,974

4 Claims. (Cl. 18-8) This invention relates to an arrangement fordrawing (cold or hot drawing) synthetic fibres, such as, mesomeric chainpolymers (Terylenes, Perlon U, L and T, Nylon), polymeric hydrocarbonsand their derivatives, polystyrol, polyvinyl chloride, polyacryliccompounds (Orlon and so forth), and all substances of similar physicalcharacteristics.

It has been found that the known drawing processes employing an agatepin, have the disadvantage of being subject to certain limitations withrespect to the speed of drawing. Since the thread to be drawn clings tothe agate pin, during the running, there is developed, with increasingspeed, a progressively increasing frictional heat, which ultimatelyleads to breakage of the thread, and is synonymous with the limitationof the speed of drawing. The friction of the thread on the agate pinalso leads to many capillary thread breakages.

Substantially better results are achieved when the arrangement fordrawing according to the invention is employed. This arrangement isfundamentally suitable both for cold drawing and for hot drawing. Animportant feature of the invention consists in that two drawing rollers,located with their axes in a plane, are provided with deflectingrollers, and that the drawing rollers, by frictional engagement with twodriving rollers, can be driven to correspond tothe draft ratio. Such anarrangement largely counteracts the tendency that is characteristic ofcustomary processes to form constrictions during the drawing process,and with such an arrangement of the drawing elements practically thesame results are attainable as regards uniformity of the titre, elasticelongation and so forth, as are expected when employing the customaryagate pin.

A further distinctive feature of this invention is that the said drawingrollers, and also the deflecting rollers, are mounted on swingablelevers, which are collectively pivoted to a vertical shaft (rotatablecolumn), and can be rotated with the rotatable column about a definiteaxis, whereby the revolving elements of the drawing arrangement aredisconnected from the drive and stopped. For the invention still furtherdetails are important, which will be hereinafter described. Forinstance, a conical or stepped construction of the lower drawing rolleris contemplated, in which case the diameter of the deflecting roller ordeflecting pin is to be maintained as small as possible.

For all the arrangements according to the invention, the following maybe set forth as important advantages:

1) Slight gripping or special stressing of the thread through frictionby drawing rollers or thread brakes at any stage of the drawing process;

(2) For piecing the broken end after breakage of thread, all the drawingelements are at rest;

(3) Substantially higher drawing speeds, and therefore substantiallyhigher dofling speeds than are attained with the arrangements hithertoknown, are yielded by (l) and (2).

By way of illustrating the arrangement according to States Patent 6 iice Patented Sept. 30, 1958 the invention, various constructions arediagrammatically represented in the accompanying drawings, in which:

Fig. 1 is a side elevational of the rotatable column, with certain ofthe components in cross-section.

Fig. 2 is a view similar to Fig. l with the rollers in the swung-offposition.

Figs. 3 to 9 inclusive are diagrammatic representations of means forpracticing the invention, with the components in the inoperativeposition, and

Fig. 10 is a diagrammatic view showing the path of forces of the threadloops about the roller b of Fig. 9.

In Figs. 1 and 2, the drawing assembly includes drawing rollers a and b,deflecting rollers s and t, and friction driving rollers c and d,respectively. The rollers a, s and b, t are carried by swing levers eand 1, respectively which levers in turn are mounted on a rotatablecolumn g. Setting screws p function as stops for limiting the swingstroke of the levers e and f and n denotes a hand grip operativelyconnected with the column g to facilitate the rotation of the column.

The rollers a and b support rubber rings a and b respectively serving toincrease the friction on the rollers c and d (Fig. 1).

In Figures 3 and 4, merely diagrammatic arrange ments are illustratedwhich are in line with the invention. The drawing rollers a and b lyingin one plane, the deflecting rollers s and t, and finally the drivingrollers c and d, which drive the rollers a and b by friction, will beseen.

Figure 5 likewise shows fundamentally the arrangement described inconnection with Fig. 3, but with the addition of an agate pin. Thisindication is given for the purpose of indicating how wide a range theapplicability of the arrangement according to the invention isavailable.

Figure 6 illustrates a somewhat modified arrangement, which howeverlikewise corresponds to the basic structure of the arrangement of theinvention. According to this form, the deflecting roller s of the feedroller a is so supported on the appropriately constructed swing leverthat the issuing of the thread from the deflecting roller in question iseffected with a suitable direction of rotation of the roller a andcorresponding guidance of the thread.

This arrangement counteracts to a great extent the tendency to formconstrictions during the drawing process, and is likewise suitable forthe cold drawing of mesomeric chain polymers.

A similar effect is obtained with the arrangement according to Figure 7,this being on the basis of the conical or stepped formation of the lowerdrawing roller b. The diameter of the deflecting roller 2 (or of thepin) is kept small. Owing to this conical formation of the drawingroller 1) the drawing procedure is separated into two continuouslysuccessive operations, percent of the draft being generally effected onthe portion a to b and 20 percent of the draft in the form ofafterdrawing within the individual loopings of the thread around thelower conical drawing roller b during the passage of the thread from bto b This arrangement has proven particularly advantageous also for thereduction of the residual elastic elongation of the drawn yarn, which isgenerally very undesirable. This is especially the case when theafter-drawing is effected under the influence of a definite temperature.

The shaping of the polymeric hydrocarbons and their derivatives can onlybe effected under the influence of a definite heat, the temperature ofwhich lies generally between and 220 C. According to the processhitherto known the procedure was to guide the thread during the drawingover a heated plate or profile body the w a'rrning of the thread had tobe higher than the' temperature that isin itself necessary for theelastic deformation of the thread or substance in question, or elsetheheating body had to be very large or very long in order to give thethread time enough, during its passage through or over the heating body,to become warmed to thet'emperature' of elastic deformation. Thearrangements hitherto known therefore constitute in general a compromisebetween a structurally more or less advantageous construction and ashigh a delivery or dofiing speed as possible; and here the question ofeasy operation in the event of breakage of thread, or in setting orstarting the operation of the machine as a whole, is of the utmostimportance. An excessive temperature, which lies even only a few degreesabove the temperature at which elastic deformation of the substance inquestion begins, has been found to be particularly disadvantageous,since the joining of the ends after breakage of thread is in particularhereby rendered exceedingly difficult; for a contact, lasting even a fewseconds, of the heating body with the thread not yet running, leads tothe thread sticking to the heating body or to breakage of thread.

All these circumstances are taken into consideration by the structureillustrated in Figure 8, owing to the fact that the deflecting rollers sand t are differently arranged and that the upper feed roller is heatedinternally, and, it may be, also heated externally, as in Figure 9.

For yarns of a general nature the internal heating of the upper feedroller a by means of a heating body w, stationary or revolving with theroller, in the interior of the roller a, as shown in Figure 8, is quitesufficient. With this arrangement delivery or dofiing speeds areattained which are much greater than those hitherto known.

For yarns or fibre bunches of great thickness, supplementary heating bymeans of an annular heating body u surrounding the upper feed roller aat a certain distance, as shown in Figure 9,, has been foundadvantageous. With this arrangement also the known dofiing speeds forthe yarns or fibres in question are greatly exceeded.

As a special feature of the novel action of this device for warming thethread or substance to be drawn, the following is set forth:

(1) A gradual warming of the thread up. to the temperature of elasticdeformation by means of multiple turns around a heated roller (seeFigure 8, the tem perature of which is approximately equal to thetemperature of elastic deformation of the substance to be drawn. Herethe gradual warming of the thread can be regulated by more or less turnsaccording to the thickness of the thread and the speed of doffing. Thesame applies in the case of supplementary heating by an encirclingannularly constructed heating body.

(2) Moreover a relatively long stoppage of the rollers, with threadslooped around the roller a, does not lead to the thread sticking to theheated surface of the roller and to consequent breakages of thread, asthe temperature is not higher than the temperature necessary for theelastic deformation of the substance to be drawn.

The high stresses occurring in the thread in the hot drawing of thethick threads or fibre bunches are important for the proper driving ofthe lower drawing roller Ii on a basis of friction by the lower drivingshaft a. By

a special arrangement of the deflecting roller t (see Figure 9) theresult is obtained that the stresses occurring in the thread work out inpart as application pressure of the roller b upon the shaft d, thispressure depending upon the number of loops of thread passing around theroller 1) and the deflecting roller 1. Due to the fact that thetension'in the thread, during the drawing process to the individualloops of thread surrounding the roller b and the deflecting roller t, itwill be noted that the sum of all these tensions. attempts to press theroller b in the direction towards the roller t. While a portion of thissum of thread tensions is taken off by the bearing of the roller 2 andover the lever f ultimately by the column g, the component vertical tothis first mentioned portion of the sum of thread tensions comes intoaction as supplementary pressure between the roller b and the lowerdriving shaft d, as can be seen from Fig. 10.

As a feature of special effect there may be adduced for thisarrangementthe fact that an application pressure, in addition to-the intrinsicweight of the roller 5 and the swing lever f, acting upon the drivingshaft d, is effected 7 Owing to the thread tension produced between thetwo rollers a and b by the drawing process, and rises or fallsproportionally with this thread tension.

We claim:

1. An apparatus for the hot or cold drawing of stretchable fullsynthetic thread's'of thermoplastic high polymers comprising a feedingroller, a drawing roller, a corresponding deflecting roller for each ofthe feeding and drawing rollers, drive means frictionally engaging saidfeeding and drawing rollers to impart movement to the same,swing'levers, means mounting the feeding roller and'its deflectingroller on one of the swing levers, means mounting the drawing roller andits reversing roller on another of the swing levers, a vertical shaft,and means pivotallymounting each swing lever to the vertical shaftwhereby said feeding and drawing rollers are both swingable about theaXis'of the vertical shaft to a degree to disconnect the feeding anddrawing rollers from the drive means and render said feeding and drawingrollers inoperative.

2.'A'n apparatus for the drawing of synthetic threads as claimedin'claim 1, characterized by the feature that the movement of each swinglever upon the rotation of the vertical shaft is limited in onedirection by a projection on the lever and a set screw on the shaftthereby insuring simultaneous starting of the feeding and drawingrollers.

3. An apparatus-for the drawing of synthetic thread as claimed in claim1, characterized by the feature that the deflecting roller associatedwith the feeding roller is journalled on the correspondingly constructedswingable lever, whereby, with a corresponding direction of rotation ofthe said feeding roller, the thread-guiding can be so effected that thedelivery of the thread is effected from the deflecting roller inquestion.

4. An apparatus for the drawing ofsynthetic threads as claimed in claim1, characterized by the feature that the lower drawing roller is ofconical formation, and that thethread runs on at the smaller diameterand runs off at the larger diameter of this roller.

References Cited in the file of this patent UNITED STATES PATENTS1,370,268 Batche'lder Mar. 1, 1921 1,889,385 Schuster Nov. 29, 19322,289,232 Babcock July 7, 1942 2,335,190 Minich Nov. 23, 1943 2,404,714Latham July 23, 1946 2,455,173 Hitt Nov. 30, 1948 2,657,451 Solliday etal. Nov. 3, 1953

